Studies of Two Kinds of Virus Particles Which Comprise Influenza A2 Virus Strains

Abstract

Two kinds of virus particles have been found in varying proportions in influenza A2 strains isolated during the 1957 pandemic. Pure populations of the different particles were obtained, and these substrains were genetically stable on serial passage in the chick embryo. The two virus particles differ markedly in several biological properties though they are antigenically similar. One kind of particle, designated "+," is relatively sensitive to specific antibody, is highly sensitive to inhibition by serum inhibitors and urinary mucoprotein, fails to elute or elutes very slowly from human erythrocytes, and is capable of agglutinating erythrocytes treated extensively with V. cholerae filtrate. The other particle, designated "-," is relatively insensitive to antibodies and urinary mucoprotein, completely insensitive to serum inhibitors, elutes rapidly from erythrocytes, and can agglutinate erythrocytes treated extensively with V. cholerae filtrate. Both "+" and "-" particles destroy virus receptors on urinary mucoprotein. The relative proportions of these two particles determine the characteristics of parent strains in reactions with specific antibody, mucoprotein inhibitors, and erythrocytes. The "+" and "-" particles with several easily identifiable markers are well suited for genetic studies.

Egg-grown and tissue-culture-grown variants of influenza A (H3N2) virus with special attention to their use as antigens in seroepidemiology

“…The molecular change that obviously determines the receptor specificity of the Q-phase variants of H3N2 subtype viruses has been described (Rogers et al 1985). In contrast to the M-virus of the present study, the Q-phase variants are poorly reactive with HI antibody and in sensitive to yinhibitors (Choppin & Tamm, 1960). This difference suggests that, in spite of the similarity in elution rate, the two viruses are not identical in their receptor specificity.…”

“…Briefly, in contrast to the E-virus, the Mvirus was incapable of agglutinating sheep erythrocytes and eluted rapidly from hen and human group-O erythrocytes. A rapid elution from erythrocytes has been 752 R. PYHALA AND OTHERS described as characteristic of Q-phase variants of H2N2 subtype human viruses (Choppin & Tamm, 1960) which, like Q-phase variants of H3N2 subtype human viruses ) as well as equine and avian isolates , bind to the NAa2,3 Gal sequence rather than the SAcc2,6 Gal sequence as preferred receptor determinant in cell-surface sialyloligosaccharides (Carroll, Higa & Paulson, 1981). The rapid elution from erythrocytes is attributed to the virus neuraminidase, which efficiently hydrolysed only the NAcx2,3 Gal linkage (Carroll, Higa & Paulson, 1981).…”

Studies of Two Kinds of Virus Particles Which Comprise Influenza A2 Virus Strains

“…The origin and isolation of these strains and substrains have been described (20,22,23). Virus preparations for electron microscopy were obtained by inoculation of 0.1 ml.…”

“…Hemagglutination Titrations.--The procedure employed has been described (20,23). Neutralization Titrations.--A constant amount of normal horse serum and serial dilutions of virus were used, and the titrations performed by the method previously described (20).…”

“…III logical characteristics of the previously described (19)(20)(21) "+" and ..... substrains of influenza A2 virus strains are presented, and lack of correlation between spherical or filamentous morphology and the other properties of these substrains is reported.…”